Longitudinal Spin Seebeck effect in Pyrochlore Iridates with Bulk and Interfacial Dzyaloshinskii-Moriya interaction

TL;DR

This paper develops a comprehensive theory of the longitudinal spin Seebeck effect in heterostructures with Dzyaloshinskii-Moriya interactions, using pyrochlore iridates as a model, highlighting the influence of crystalline orientation and interfacial anisotropy.

Contribution

It introduces a generalized model incorporating anisotropic Dzyaloshinskii-Moriya interactions at interfaces, extending previous isotropic assumptions in SSE theory.

Findings

Spin current depends on temperature and bulk DMI strength.

Crystalline orientation significantly affects spin transfer.

Interfacial moment and DMI vector angles are crucial for spin transfer efficiency.

Abstract

The longitudinal spin-Seebeck effect (SSE) in magnetic insulator$|$non-magnetic metal heterostructures has been theoretically studied primarily with the assumption of an isotropic interfacial exchange coupling. Here, we present a general theory of the SSE in the case of an antisymmetric Dzyaloshinskii-Moriya interaction (DMI) at the interface, in addition to the usual Heisenberg form. We numerically evaluate the dependence of the spin current on the temperature and bulk DMI using a pyrochlore iridate as a model insulator with all-in all-out (AIAO) ground state configuration. We also compare the results of different crystalline surfaces arising from different crystalline orientations and conclude that the relative angles between the interfacial moments and Dzyaloshinskii-Moriya vectors play a significant role in the spin transfer. Our work extends the theory of the SSE by including the anisotropic nature of the interfacial Dzyaloshinskii-Moriya exchange interaction in magnetic insulator$|$non-magnetic metal heterostructures and can suggest possible materials to optimize the interfacial spin transfer in spintronic devices.